Conspicuous by Their Absence

Hello Womble55,
We all develop more skills and understanding of how things work in the flight sims if we are willing to mess around a bit and see what the result is. I have no idea what the proper fuel capacity information is for the Wellesley Mk.I or which ever Mark it is that you are modelling. Searching the Internet hasn't produced anything for me yet. It just occurred to me that I might have one more source which I will check before I go to bed.

I was looking back over the start of the discussion about the Wellesley and it engine power output. If the Engine Tuning Tutorial didn't help, I believe the issue is that the manifold pressure of the Pegasus engine is much much lower than that of the Merlin in the P-51D. I will see if I can come up with any numbers there as well.

As for ammunition load for the Wellesley, I am guessing that it carried a LOT of ammunition for the two .303 machineguns that were mounted. This is the kind of aeroplane the British tended to use in remote areas without good supplies.
I have .303 British Ammunition as weighing 1.05 ounces per round and link.

Hope this helps. I will post additional data if I can find it.
- Ivan.
 
With all of the trawling of the internet, all I can find for the Wellesley is 3000 rounds of ammunition but this is on one site only.
The fuel load, I think, is around 450 gallons (this was done by reverse mathematics from info gleaned from one site that said the fuel load for the LRDU was increased by x amount) but the quantity distribution still eludes me.
On the plus side, I have increased the wing tankage to an initial 220 gallons and reduced the aileron sensitivity and she flies much better.
Thanks for the pointer regarding the specifics of the Bristol Pegasus, hopefully I can get the engine tuned correctly.
On the down side, I'm back from holiday and I am now getting ready for work.
 
Vickers Wellesley

Hello Womble55,

I don't believe you understood what I was getting at. The Aileron Control Effect is one thing, but the Roll Damping (Record 1001?) is what I believe should be changed. Even if the Ailerons were just as powerful, double the wingspan and about three times the area is going to slow things down a bit.

Here is what I could find about the Bristol Pegasus XX:
Bore: 5.75 inch
Stroke: 7.50 inch
Diameter: 55.3 inch (For the visual model)

0.5 : 1 Reduction Ratio.
87 octane fuel.

Ratings (From Janes):
925 HP @ 2475 RPM for Take-Off (but note that Max RPM is 2600 so why is Take-Off Limit so low?)
815 HP @ 2475 RPM Climb Power (@ 4500 feet altitude)
575 HP @ 2200 RPM Cruise Power (@ 9250 feet altitude)

Janes says 860 HP @ 2600 RPM for all out power, but I believe this is a typo.
I believe 960 HP is what was intended.
See the attached graph for manifold pressure settings (+4.25 pounds) and rated altitude (8500 feet).
I have a conversion spreadsheet for pounds boost to inches Mercury in the Engine Performance Tuning Tutorial.
I believe the graph agrees more with 960 HP as all out power.

From the graph, I believe there is sufficient information to generate a pretty good CFS engine.
The original graph was too high resolution to upload so I had to reduce and rotate.
Funny thing is that this upload is about 100K heavier than the original.
Let me know if you want the original which isn't any more readable than this one.

Hope this helps.
- Ivan.
 
Hi Ivan,
I had all of the Bristol Pegasus specs from Wikipedia, they said more or less the same. Wikipedia is a great source for all aero engines including the more obscure like the Armstrong Deerhound and Boarhound.
What I have found though is the ammunition load out for the Wellesley, not on the Internet but with good old paper and ink. I managed to get hold of 'Warpaint No 86' from eBay and its an absolute gem.
The front gun (Browning) had 97 rounds whereas the rear gun (Vickers) had a total of 600 rounds. I believe the information to be correct and just plainly disbelieve what was found on the internet.
The flying has improved greatly by decreasing the values in 1001, to such an extent that long distance flights are a pleasure to do.
I still have some bleed issues, some missing panels have been sorted plus a couple of small items still to build.
I can see the light at the end of the tunnel.
 
Hello Womble55,

I am pleasantly surprised that Wikipedia has that much information on the Bristol Pegasus.
The only thing I found that they didn't list was the Manifold Pressures.
Did you ever find the Propeller Pitch Range? I never found that OR the Propeler Diameter.

Regarding the ammunition loadouts: I am a bit skeptical about 97 rounds on the fixed Browning MG.
Considering that the Browning fired at around 1200 rounds per minute cyclic rate, 97 rounds gives not quite 5 seconds of fire. I was guessing around 2000 rounds but your 3000 rounds sounded quite reasonable.

- Ivan.
 
Hi Ivan,
I was surprised at 97 rounds too but further into the book it states that the forward firing browning ammunition box contained 650 rounds. It also states that the propeller was a De Havilland ( Hamilton Standard) two position prop of 12ft 6ins diameter. As for the pitch angles, that one eludes me.......for now.

Ps. After a swift search I have found that Hamilton Standards had a pitch range of 15 degrees to 45 degrees, this is for the constant speed units and not the two pitch type so further research is required.
 
I don't believe all Hamilton Standard Propellers had the same pitch ranges. Note that the propellers on the Japanese A6M Type Zero Fighter only had a range of about 20 degrees and for the A6M5 was 29-49 degrees. This is a pretty reliable number since it is from their own operations manual for the type.

It is also possible to have the pitch range out of adjustment as was done with the A6M2 captured by the AVG and tested.
This implies that the low and high pitch stops were changeable and might vary significantly between types.

- Ivan.
 
Hi everyone, as promised here is an early version of my Vickers Wellesley. There is still a lot to do, bleeds, minor construction alterations and the usual tweeks to get things right. The Air file isn't quite right but I am working on it as we speak.
This is one of the aircraft that I believe to be missing from our hangers for way too long, the aircraft from the late twenties and early thirties are sadly lacking. A shame really because the majority of aircraft that we do have in our hangers wouldn't be there if it wasn't for the missing examples.
 
Hello Womble55,

Cool Aeroplane! This thing is HUGE!

I poked around at it a couple hours ago and found a few issues that don't look difficult to fix.
Should I email you? Don't know if I still have your email address.

- Ivan.
 
Hello Womble55,

Is this one also yours? I believe this project has been on my computer since about 2006.

- Ivan.
 
Ivan said:
Hello Womble55,

Is this one also yours? I believe this project has been on my computer since about 2006.

- Ivan.
Click to expand...

Yes, the project has been going for an embarrassing long time and has had new engine, wings, cockpits, fuselage. In fact it has been rebuilt more times as and when my skills improved. Most of this was due to the lack of a decent drawing of the correct Mk1 and not of the prototype or one from the LRDU or the Bristol Hercules test bed.
 
Hi everyone, must thank Ivan for the Air file pointers, the Wellesley flies like a dream. I have rebuilt the rear fuselage, added blanking for the cockpits and at the moment trying to sort out the U/C bleeds. Hopefully it will be uploaded in the near future.
 
Experiments with AIR File

Hello Womble55,

I actually spent a fair amount of time poking at the Wellesley AIR file because I thought it would be a good test of whether I could easily accomplish again what I described in the Engine Tuning Tutorial. It was fairly easy.

The other thing I noticed about the Wellesley was that it had a large wingspan with very minimal dihedral. I believe an aircraft like that tends to have a flat yaw from rudder input alone and because the original came from the stock P51D, it needed a fair amount of tuning.
I was trying to see if my process for tuning the B-25C Mitchell was reproducible. With a bit of effort, I found that a lot of my notes were not quite thorough enough and some were outright wrong. I got more or less the effect I was looking for with the Wellesley.

Tonight, I went back to see if my additional notes from the Wellesley would make fine tuning the B-25 easy. Turns out that they do not. Just about every change I made had some kind of unintended side effect. Yet more refining is necessary and I am back pretty much to where I started with the MitchellC's AIR file....

I just hate it whennat happens!
- Ivan.
 
Last Few Days

This is a bit off topic, but here goes:

The last few days have been a bit rough around our household.
My 11 year old son had very bad stomach pains and had to go to the Emergency Room.
Turns out he had appendicitis and had to have surgery to remove his appendix.
It is hard knowing someone is about to cut open your little baby even if he needs the surgery.

We got back from the hospital yesterday and although he is still in some serious pain, he seems to be getting better. He can barely walk right now so he will be out of school for a couple days more.

He still doesn't eat much but that appears to be improving as well.

- Ivan.
 
Standing with you Ivan. I'm sure the 'little fella' will be up and causing chaos before you know it! Youngsters bounce back so quickly. Enjoy the peace and quiet while you can.

Best Wishes,

Graham.
 
hello Ivan,
i'm so glad to hear that the young cfser is on the mend.
it must have been real scary for you all.
is mama still out of town?

best wishes for a speedy recovery.
 
Ivan said:
This is a bit off topic, but here goes:

The last few days have been a bit rough around our household.
My 11 year old son had very bad stomach pains and had to go to the Emergency Room.
Turns out he had appendicitis and had to have surgery to remove his appendix.
It is hard knowing someone is about to cut open your little baby even if he needs the surgery.

We got back from the hospital yesterday and although he is still in some serious pain, he seems to be getting better. He can barely walk right now so he will be out of school for a couple days more.

He still doesn't eat much but that appears to be improving as well.

- Ivan.
Click to expand...

Can't put myself in your shoes, but I surely can imagine how nerve-wrecking it was. Hang in there Ivan:173go1:!!!
 
Today was the first day he could climb stairs.
He was only 68 pounds before this trip to the hospital and he hasn't been eating much since he got back. Hope he is still over 60 pounds now.
Every day he gets a bit stronger, but I believe we will be keeping him home for one more day.

Mom has been home for a while. I would have been much more hesitant than mom for a trip to the Emergency Room.
Glad she was here so we could swap off babysitting duties.

Thanks Guys.
- Ivan.
 
Landing Gear Tuning

After running into a few CFS aircraft that appeared to fly fairly well but didn't sit still on the ground, I decided to do a few experiments to see if I could formalise the process that I have been using for tuning.

For test subjects to use in tuning, I was looking for aircraft that exhibited shaking and vibrations while just sitting on the runway with the engine off. There are also some that don't visibly shake but will rotate a fair amount if left unattended.

I worked on a few spreadsheets to calculate the numbers to plug in to various records and believed that I had gotten the process to be pretty reliable with no guessing required.

After a few successful tests, I asked my son if he knew of a "vibrating or nervous" aircraft. He gave me a FW 190D-9 "Dora". He could not turn from where he was laying to observe what I was trying to do and also was a bit more interested in other video games at the time.

The next morning, I explained what I was trying to do and showed him the result: a FW 190D "Dora" that didn't bounce any more. I tried explaining the factors that I was adjusting.

The following day (Today), he told me that he called this particular FW 190D "Bouncy" and liked seeing it bounce. I explained how the bounce was a mistake by the designer, but he still wanted a bouncy aeroplane.
I guess tomorrow I get to restore the bounce.

Up to this point, I had thought this would make an interesting tutorial.

Kids WILL surprise you!

Sheesh!
- Ivan.
 
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